Gas turbine engines include a turbine having multiple blades attached to a central rotor. Hot combustion gases from a number of combustors flow through the blades so as to induce the rotor to rotate. Minimizing the volume of the hot combustion gases bypassing the blades may enhance the overall energy transfer from the hot combustion gas flow to the turbine rotor. A turbine shroud therefore may be positioned within a turbine casing so as to reduce the clearance between the turbine blade tips and the casing.
Similarly, the rotating components in the hot gas path and the associated shrouds may experience wear and tear under the elevated temperatures of typical operation. These hot gas path components generally may be cooled by a parasitic flow of cooling fluid from the compressor or elsewhere. The overall efficiency of the gas turbine engine therefore may be increased by both limiting the clearance between the blades and the shrouds and by limiting the flow of cooling fluids to cool the hot gas path components.
There is thus a desire for improved methods and systems of cooling gas turbine shrouds and related components. Preferably such systems and methods may cool the shrouds with reduced variability in the cooling flow and with reduced installation and maintenance costs.